Caption: Saturn and moon transits, Hubble Space Telescope (HST) image. Saturn, a large ringed gas giant planet, has a diameter of over 120,000 kilometres. Four of its moons are seen here, in a rare transit alignment visible from Earth. At upper right is the moon Titan (orange). At far left are two dots (white) with corresponding shadows: Enceladus (left) and Dione (right). At far right, just on the edge of the planetary orb and near the rings, is the moon Mimas (white dot). Image obtained on 24 February 2009, with Hubble's Wide Field Planetary Camera 2 (WEPC2). The distance to Saturn was around 1.25 billion kilometres.